Pump, diffusion radial

Figure 7.10. Some types of impellers for centrifugal pumps, (a) Open impeller, (b) Semiopen impeller, (c) Shrouded impeller, (d) Axial flow (propeller) type, (e) Combined axial and radial flow, open type, (f) Shrouded mixed-flow impeller, (g) Shrouded impeller (P) in a case with diffuser vanes (V). (h) Turbine impeller.

A rotated disc in a fluid behaves as a pump which draws fluid towards the disc and throws it out radially, Fig. 5.17. Flow to a rotated disc has the surprising property that, under laminar flow conditions, the film thickness is uniform across the whole of the disc surface, excluding edge eifects, and the film thickness (5) is rigorously calculable using fluid mechanics theory [22]. ft is given by Equation 5.12 where D is the diffusion coefficient in cm2 s-1, v is the kinematic viscosity in cm2 s 1 and a> is the rotation speed in rad s-1 ... 

A practical difficulty, encountered in this study was performing the AUC runs at temperatures higher than 40 °C at such high temperatures, the oil vapors from the diffusion pump interfere with the UV absorption optics. They circumvented this problem by using a different type of optical scanning known as the Schlieren optics, which generates the data as profiles of radial derivative of concentration distributions as a function of radius (as opposed to the concentration versus radius scans obtained from UV optics). 

Vacuum pumps are generally divided into 13 categories according to the working principle, as listed in Table 2.5. They include water jet pump, water ring pump, steam ejector, oil-sealed rotaiy pump, Roots pump, vacuum diffusion pump, oil vapom booster pump, sputtering-ion pump, radial field pump, titanium sublimation pump, sorption pump, molecular pump and cryopump [9],... 

Fig. 18. Diagram of reactive scattering apparatus for the study of non-metal reactions A, scattering chamber B, source chambers C, liquid nitrogen cooled cold shield D, detector E, source bulkheads G, liquid nitrogen trap H, oil diffusion pumps N, free radical source P, nozzle source Q, skimmer E, ion source H, liquid He trap I, ion lenses P, photomultiplier Q, quadrupole rods R, light baffle S, slide valve T, radial electric field pumps (from C. F. Carter et al. 02 by permission of the Chemical...

The liquid flow pattern in a bubble column of 15 cm diameter was investigated by Kojima et al. [63] at superficial liquid and gas velocites of the order of 1 cm/s. The liquid flow was found to be complicated and to vary continuously with time. The flow was mainly upward in the central part, but in other parts both upward and downward, although mainly downward near the wall. Radial flow was present across the entire cross section as a result of the pumping effect of the wakes of bubble swarms when the volume of liquid pumped per unit time by the wakes of the bubbles exceeds that of the liquid fed, downward flow has to occur, inducing radial flow. These observations confirm those of Towell and Ackerman [64] who, in addition, expressed the mixing in terms of axial effective diffusivities for the... 

There is, in principal, an alternative to the rotation of the disc, which is the rotation of the electrolyte. But just rotation of the electrolyte would not lead to similar diffusion conditions because the electrolyte, stopped at the walls of the cell, would develop a different radial flow profile. The generation of the same diffusion layer by rotation of the electrolyte was achieved by a special rotating pumping system as shown in Figure 5.24. ... 

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